Video synopsis (or abstraction) is a temporally compact representation that aims to enable video browsing and retrieval.
There are two main approaches for video synopsis. In one approach, a set of salient images (key frames) is selected from the original video sequence. The key frames that are selected are the ones that best represent the video [7, 18]. In another approach a collection of short video sequences is selected [15]. The second approach is less compact, but gives a better impression of the scene dynamics. Those approaches (and others) are described in comprehensive surveys on video abstraction [10, 11].
In both approaches above, entire frames are used as the fundamental building blocks. A different methodology uses mosaic images together with some meta-data for video indexing [6, 13, 12]. In this methodology the static synopsis image includes objects from different times.
Object-based approaches are also known in which objects are extracted from the input video [7, 5, 16]. However, these methods use object detection for identifying significant key frames and do not combine activities from different time intervals.
Methods are also known in the art for creating a single panoramic image using iterated min-cuts [1] and for creating a panoramic movie using iterated min-cuts [2]. In both methods, a problem with exponential complexity (in the number of input frames) is approximated and therefore they are more appropriate to a small number of frames. Related work in this field is associated with combining two movies using min-cut [20].
WO2006/048875 [14] discloses a method and system for manipulating the temporal flow in a video. A first sequence of video frames of a first dynamic scene is transformed to a second sequence of video frames depicting a second dynamic scene such that in one aspect, for at least one feature in the first dynamic scene respective portions of the first sequence of video frames are sampled at a different rate than surrounding portions of the first sequence of video frames; and the sampled portions are copied to a corresponding frame of the second sequence. This allows the temporal synchrony of features in a dynamic scene to be changed.